meshio++I/O and operations for many mesh formats

One unified mesh data model, 87 file formats, 47 mesh and 6 data operations, a fast C++ core with pure-Python fallbacks, and six language surfaces over it.

Quickstart

Architecture

Supported formats

GitHub

🗂️

87 formats

Read 81 and write 73 mesh formats — VTK, VTU, XDMF, Gmsh, MED, Exodus, CGNS, Abaqus, Nastran, UNV, OpenFOAM, GiD, COMSOL, FLUX and more — through a single API, with per-format options where the format has them.

🧩

One data model

A single Mesh (points, cell blocks, point and cell data, field data, named regions of points, cells or sides) bridges every format, so conversion is one call and a group survives the round trip.

⚡

Fast C++ core, Python fallbacks

A C++20 core behind a pybind11 extension with zero-copy numpy at the I/O boundary, optional HDF5, netCDF and compression codecs, and a pure-Python reference implementation for every format.

🛠️

45 mesh + 6 data operations

Quality, skin and surface extraction, reordering, cleaning, cropping, splitting, partitioning, refinement and coarsening, decimation, remeshing, smoothing, slicing, isosurfaces, gradients, interpolation, curvature, normals, repair, shrinkwrap, Sobolev deformation and tensor invariants, on every surface.

🌐

Six language surfaces

Python, a pure-C99 API with a versioned ABI, Fortran, Julia, R and a WebAssembly package, plus an installable C++ API and a single-header build, all over the same core and the same format registry.

⌨️

Two CLIs and a pipeline engine

A Python CLI and a Python-free native binary with the same verbs, a declarative settings.json pipeline that every surface runs, and a sequence driver for transient, multi-file datasets.

👁️

Viewers, Blender, ParaView

A browser viewer and dataset manager on the WebAssembly build, a Polyscope desktop viewer, a Blender 4.2+ add-on and a ParaView reader plugin.

🤖

Built for agents and ML

An MCP server exposing every operation as a file-path-based tool, zero-copy interop with PyVista, trimesh, Arrow and pandas, DLPack and CuPy handoff, graph and feature-matrix export, and a PhysicsNeMo adapter.

What is meshio++?

meshio++ reads and writes unstructured mesh files. It supports 87 formats through one unified data model, so you can convert between any of them and run the same operations on the result, from the command line or from Python:

python

import meshioplusplus

mesh = meshioplusplus.read("input.msh")   # format inferred from the extension
mesh.write("output.vtu")

meshioplusplus convert input.msh output.vtu
meshioplusplus info input.xdmf

Under the Python API sits one C++ core with six language surfaces on top of it, and the tools — CLIs, viewers, an MCP server, a Blender add-on — are built on those surfaces:

meshio++ architecture: one C++ core, six language surfaces, and the tools built on them

See the Quickstart to get going, the Architecture page for the map, the Supported formats table for the full list and per-format options, and the CLI reference for the command-line tools.